1. Field of the Invention
This invention relates to the use of selected metal compounds as modifiers for preparing high impact resistant nylon-6 or nylon-66 molding compositions.
2. Brief Description of the Prior Art
It is known (U.S. Pat. No. 3,388,186 issued June 11, 1968 to Kray et al.) that compositions of nylon-6, containing ethylene copolymers having a minor proportion of acrylic or methacrylic acid or alkyl ester thereof as backbone and having grafted nylon-6 side chains, show higher impact resistance than nylon-6 molding compositions not containing the above graft copolymers. These compositions are prepared by reacting caprolactam in the ethylene copolymer melt.
U.S. Pat. No. 3,472,916 of Oct. 14, 1969 to Anspon et al. discloses blends of 70-98% by weight nylon-6 homopolymer with correspondingly 2-30% by weight of ethylene/acrylic or methacrylic alkyl ester copolymer, having improved Izod impact resistance, compared to nylon-6 alone. The alkyl group in the alkyl ester copolymer contains 1-4 carbon atoms and the alkyl ester is from 10 to 60 percent by weight of the copolymer. The copolymer has "highly uniform distribution of the acrylic ester in the copolymer", presumably a random distribution. These blends are prepared by mixing together and subsequently co-extruding the ingredients.
U.S. Pat. No. 3,963,799 issued June 15, 1976 to Starkweather, discloses ternary blends of polyamide, polyethylene or copolymers thereof, and a small amount of copolymer having an ethylenic backbone and nylon-6 side chains.
Also, U.S. Pat. No. 4,160,790, incorporated herein by reference, discloses synergistic improvement of nylon-6 or nylon-66 impact resistance by blending, in the melt, with minor proportions of both an ethylene/acrylic acid copolymer and an ethylene/ethyl acrylate copolymer.
French Pat. No. 1,386,563, of issue date Dec. 14, 1964, relates to compositions of 50-99 percent by weight polyamide and the balance an olefin copolymer containing up to 10 mol percent of acid side chains.
Journal of Polymer Science, Volume 54, Pages 388 and 389 (1961) in an article entitled "Linear Polyesters", by R. E. Wilfong, discloses a list of catalytic agents including various metal oxides suitable for use in the preparation of polyesters.
None of the above references disclose the use of metal compounds to enhance the impact resistance of nylon-6 or nylon-66 polyamide compositions with both a copolymer of an olefin and an acid-containing comonomer and a copolymer of an olefin and a C.sub.1 -C.sub.4 alkyl ester of said acid comonomer. The compositions of the present invention are useful as containers, e.g. bottles, or as film wrapping or as fibers.